Malbec vineyards grown in hot regions (Ayalon valley, Israel) tend to bear high yields, thus in some cases negatively affecting wine quality. In the current work we describe, the use of late shoot pruning (LSP) agro technique practice implied for wine quality improvement. We examined the effect of timing of LSP on Malbec vines for four consecutive years (2016-2019). LSP (applied one, two or three weeks after bud break, E-L stage 4) were compared with standard winter pruning practice (WP) and cluster-thinned winter-pruned vines (WP+T). LSP vines postponed the onset of shoot growth, but the onset of veraison in the LSP vines occurred at the same time as in the control vines. Midday stem water potential indicated less stressed vines and stomatal conductance and CO2 assimilation rate were improved in the LSP vines than in the controls. The LSP practice led to a substantial reduction of the number of clusters and of crop yield. The accumulation rate of soluble sugars in the grapes was higher in the LSP and WP+T treatments than in the WP control. The improved quality of the must components in the LSP treatments (higher titratable acid content, greater red color, lower pH in most years) was also evident in the wines produced. The LSP vines reached a higher total score of the organoleptic test. Our results show that performing the simple and cheap agro technique of LSP at the precise timing after bud burst saved labor, decreased crop yield and improved wine quality in ‘Malbec’ vineyards. LSP application should be considered a significant tool in enhanced effectiveness of vine growing in warm regions.
